Common Faults and Treatment Methods for Hydraulic Accumulators

Taking the hydraulic accumulator as an example, this article describes common faults and troubleshooting methods for accumulators. Other types of accumulators can be referenced accordingly.

Q1: The pressure of the bladder accumulator drops severely, requiring frequent recharging.

For a bladder accumulator, the bladder's charging valve is a check valve type, sealed by a conical sealing surface. During operation, vibration may cause the valve core to loosen, preventing the sealing conical surface 1 from sealing tightly and causing air leakage. Grooves on the valve core's conical surface or debris on the surface can also cause leaks. In this case, a hard rubber gasket 5 with a thickness of about 3mm can be inserted into the sealing cover 4 of the charging valve, and the sealing conical surface can be ground to ensure a tight seal. Additionally, if the upper nut 3 of the valve core becomes loose, or the spring 2 is broken or missing, the N2 in the bladder may be released instantly.

Q2: Short bladder service life

The influencing factors include bladder quality, the compatibility between the working medium used by the Ningbo bladder accumulator company and the bladder material; or the infiltration of debris; an incorrect nominal volume of the accumulator (oil port flow velocity should not exceed 7m/s); oil temperature being too high or too low; when used for energy storage, whether the reciprocating frequency exceeds 1 time/10s (if it does, the service life begins to decrease; if it exceeds 1 time/3s, the service life drops sharply); whether the installation is proper and if the piping design is reasonable, etc.

In addition, to ensure the accumulator works reliably under operating pressure and to prevent the bladder from frequently colliding with the accumulator's poppet valve during operation, thereby extending the bladder's service life, p0 should generally be selected within the range of 0.75~0.91. To prevent the bladder's contraction and expansion amplitude from being too large during operation and affecting its mission, ensure that p0 > 25%p1 > 33%p2.

Q3: Accumulator failure

The main causes are severe air valve leakage, no N2 in the bladder, and bladder damage allowing oil ingress. Additionally, when p0 > p2, meaning the maximum operating pressure is too low, the accumulator completely loses its energy storage function (no energy can be stored).

Q4: Poor effect in absorbing pressure pulsation

To maximize the accumulator's effect in absorbing pulsating pressure, the connecting pipe between the accumulator and the main line branch point should be short, and the nominal diameter should be appropriately large. It should also be installed close to the pulsation source. Otherwise, its effect in eliminating pressure pulsation will be poor, and it may even exacerbate the pressure pulsation at times.